CHANDRAYAAN - 2

 INTRODUCTION:

Chandrayaan 2 is India’s second lunar exploration mission after Chandrayaan 1. Developed by the Indian space research organisation (ISRO), the mission was launched from the second launch pad at Satish Dhawan Space Centre on 22^nd July 2019 at 2:43 P.M.  IST (09:13 UTC) to the moon by Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk-III). The planned  orbit has a very perigee of 169.7 km and an apogee of 45475 km. It consists of a lunar orbiter, lander and rover, all developed in India. The main scientific objective is to map the location and abundance of lunar water.

The lander and the rover will land near lunar south pole in a high plane between two craters, Manzinus C and Simpelius N, at a latitude of about 70 degree south on 7^th September, 2019 . The wheeled rover will move on the lunar surface and will perform on – site chemical analyses for a period of 14 days (1 Lunar Day). It can relay data to earth through the chandrayaan -2 orbiter and  lander, which will fly on the same lauch. The orbiter will keep working on its mission  for  1 year in a circularized lunar polar orbit of 100*100 km.

Launch of Chandrayaan 2 was originally scheduled for 14 July 2019 at 21:21 UTC (15 July 2019 2:51 IST) but was called off due to technical snag notice around 56 minutes before launch. It was launched on 22 July 2019 14:43 IST (09:13 UTC) from the Salish Dawan Space Centre at Sriharikota in Nellore district of Andhra Pradesh.

A successful landing would make India the 4^th country to achieve a soft landing on the moon after the space agency of the USSR, US and CHINA. If successful, chandrayaan 2 will be the southernmost lunar landing, aiming to land at 67 degree South or 70 degree south latitude.

HISTORY:

On 12^th November 2007, representatives of the Russian Federal Space Agency (Roscomos) and ISRO signed an agreement for the two agencies to work together on the Chandrayaan-2 projects. ISRO would have the prime responsibility for the orbiter and rover, while Roscosmos was to provide the lander. The Indian government approved the mission in a meeting of the Union Cabinet, held on 18 September 2008 and chaired by Prime Minister Manmohan Singh. The design of the spacecraft was completed in August 2009, with scientists of both countries conducting a joint review.

Although ISRO finalised the payload for Chandrayaan-2 per schedule, the mission was postponed in January 2013 and rescheduled to 2016 because Russia was unable to develop the lander on time. Roscosmos later withdrew in wake of the failure of the Fobos-Grunt mission to Mars, since the technical aspects connected with the Fobos-Grunt mission were also used in the lunar projects, which needed to be reviewed. When Russia cited its inability to provide the Lander even by 2015, India decided to develop the lunar mission independently.

The spacecraft’s launched had been scheduled for March 2018, but was first delayed to April and then to October to conduct further tests on the vehicle. On 19 June 2018, after the program’s fourth Comprehensive Technical Review meeting, a number of changes in configuration and landing sequence were planned for implementation, pushing the launch to the first half of 2019. Two of the lander’s legs got minor damage during one of the tests in February 2019.

Chandrayaan-2 launch was initially schedule for 14 July 2019, 21:21 UTC (15 July 2019 at  02:51 IST local time),with the landing expected on 6 September 2019. However, the launch was aborted due to a technical glitch and rescheduled to 22 July 2019.

The technical glitch was later clarified to be a leak in the 'nipple joint' of the helium gas bottle. The leak was not serious enough to impair the mission, however "abundant caution" was exercised due to the importance of the mission. It is speculated that the leak might have been caused due to the micro-shrinkage of the joint which could occur at low temperature. The proximity of the 'nipple joint' to the oxidiser tank, which contains liquid oxygen at -183°C, could have induced such a low temperature. Chandrayaan-2 was successfully launched on board by the GSLVMk-III M1 launch vehicle on 22 July 2019 at 09:13 UTC (14:43IST).

  

 OBJECTIVES:

The primary objectives of Chandrayaan-2 are to demonstrate the ability to soft-land on the lunar surface and operate a robotic rover on the surface. Scientific goals include studies of lunar topography, mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxyl and water ice. The orbiter will map the lunar surface and help to prepare 3D maps of it. The on board radar will also map the surface while studying the water ice in the south polar region and thickness of the lunar regolith on the surface. Chandrayaan-2 will in form the location and Abundance of lunar water for exploitation by the future lunar base proposed by the Artemis program.

DESIGN:

The mission is planned to fly on a Geosynchronous Satellite Launch Vehicle MarkIII (GSLVMk III) with an approximate lift-off mass of 3,850 kg (8,490 lb) from Satish Dhawan Space Centre on Sriharikota Island. As of June 2019, the mission has an allocated cost of Rs 978 crore (approximately US $141 million) which includes 603 crore for space segment and 375 crore as launch costs on GSLVMk-III. Chandrayaan-2 stack would be initially put in an Earth parking orbit of 170 km perigee and 40,400 km apogee by the launch vehicle. It will then perform orbit-raising operations followed by trans-lunar injection using it's own power.

 ORBITER:

The orbiter will orbit the Moon at an altitude of 100 km (62 mi). The orbiter carries five scientific instruments. Three of them are new, while two others are improved versions of those flown on Chandrayaan-1. The approximate launch mass will be 2,379 kg (5,245 lb). The Orbiter High Resolution Camera (OHRC) will conduct high-resolution observations of the landing site prior to separation of the lander from the orbiter. The orbiter's structure was manufactured by Hindustan Aeronautics Limited and delivered to ISRO Satellite Centre on 22 June 2015.  

VIKRAM LANDER:

The mission's lander is called Vikram named after Vikram Sarabhai (1919–1971), who is widely regarded as the father of the Indian space programme.

The Vikram lander will detach from the orbiter and descend to a lunar orbit of 30 km×100 km (19 mi×62 mi) using its 800 N (180 lbf) liquid main engines. It will then perform a comprehensive check of all its on-board systems before attempting a soft landing, deploy the rover, and perform scientific activities for approximately 14 days. The approximate combined  mass of the lander and rover is 1,471 kg (3,243 lb).

The preliminary configuration study of the lander was completed in 2013 by the Space Applications Centre (SAC) in Ahmedabad. The lander's propulsion system consists of eight 50 N (11 lbf) thrusters for attitude control and five 800 N (180 lbf) liquid main engines derived from ISRO's 440 N (99 lbf) Liquid Apogee Motor. Initially, the lander design employed four main liquid engines, but a centrally mounted engine was added to handle new requirements of having to orbit the Moon before landing. The additional engine is expected to mitigate upward draft of lunar dust during the soft landing. Vikram can safely land on slopes upto 12°.

Some associated technologies include a high resolution camera, Lander Hazard Detection Avoidance Camera (LHDAC), Lander Position Detection Camera (LPDC), an 800 N throttleable liquid main engine, attitude thrusters, Ka band radio altimeter (KaRA), Laser Inertial Reference & Accelerometer Package (LIRAP), and the software needed to run these components. Engineering models of the lander began undergoing ground and aerial test’s in late October 2016, in Challakere in the Chitradurga district of Karnataka. ISRO created roughly 10 craters on the surface to help assess the ability of the lander's sensors to select a landing site.

Dimensions: 2.54×2×1.2m

Gross lift-off mass: 1,471 kg (3,243 lb)

Propellant mass: 845 kg (1,863 lb)

Drymass: 626 kg(1,380 lb)

Power generation capability: 650 W

PRAGYAN ROVER: 

The mission's rover is called Pragyan. The rover's mass is about 27 kg (60 lb) and will operate on solar power. The rover will move on 6 wheels traversing 500 meters on the lunar surface at the rate of 1 cm\sec, performing on-site chemical analysis and sending the data to the lander, which will relay it to the Earth station.

     

SUBMITTED BY:

SHYAMA DINESHAN
SUSHMITHA  K

SUSHMITHA M

VEEKSHITH P
YOGISHA K 

TEJA

Reference: Journal

                          Internet
https://medium.com

                                              

UAV (UNMANNED AERIAL VEHICLES)

INTRODUCTION

Drones have been around for years and they are used for different purposes and can be of help in numerous occasions. However, these devices have become more popular in recent times and their application increases rapidly in various fields. But first of all let's answer the main question: "What is a drone and how we can define it?"

The word ‘drones' has several different meanings and it origins from old English word darn, which means 'male bee'. Drone is an aircraft that does not have a pilot but is controlled by someone on the ground, used especially for dropping bombs or for surveillance. Drones are more formally known as unmanned aerial vehicles (UAVs) or unmanned aircraft systems (UASes). Essentially, a drone is a flying robot. The aircrafts may be remotely controlled or can fly autonomously through software-controlled flight plans in their embedded systems working in conjunction with onboard sensors and GPS.

Physics behind the drone: Drones uses rotors for propulsion and control. We can think rotor as a fan. If you observe drone, you will find that each drone consist of four rotors. The spinning blades push the air, down. Of course, all the forces come in pair, which means that as the rotor pushes down on the air, the air pushes up the rotor. This is the basic idea behind lift, which comes down to controlling the upward and downward force. The faster the rotor spins, the greater is the Lift, and vice-versa. For a drone to hover, the net thrust of the four rotors pushing the drone must be equal to the gravitational force pulling it down. For the descending of the drone, the process is exactly opposite: i.e, simply decreasing the rotor thrust (speed) so the net force is downward.    

Uses have included remote sensing for Earth Sciences studies, hyper spectral imaging’s for agriculture monitoring, tracking of severe storms and serving as telecommunications relay platforms.

An agricultural drone is an unmanned aerial vehicle applied to farming in order to help increase crop production and monitor crop growth. Sensors and digital imaging capabilities can give farmers a richer picture of their fields. Thus, these views can assist in assessing crop growth and production. Some of the main applications are given below:

AERIAL PHOTOGRAPHY

Drones are now being used to capture footage that would otherwise require expensive helicopters and cranes. Fast paced action and sci-fi scenes are filmed by aerial drones, thus making cinematography easier. These autonomous flying devices are also used in real estate and sports photography. Furthermore, journalists are considering the use of drones for collecting footage and information in live broadcasts.

SHIPPING AND DELIVERY

Major companies like Amazon, UPS, and DHL are in favor of drone delivery. Drones could save a lot of manpower and shift unnecessary road traffic to the sky. Besides, they can be used over smaller distances to deliver small packages, food, letters, medicines, beverages and the like.

                                 

GEOGRAPHIC MAPPING

Available to amateurs and professionals, drones can acquire very high-resolution data and download imagery in difficult to reach locations like coastlines, mountaintops, and islands. They are also used to create 3D maps and contribute to crowd sourced mapping applications.

DISASTER MANAGEMENT

Drones provide quick means, after a natural or man-made disaster, to gather information and navigate debris and rubble to look for injured victims. Its high definition cameras, sensors, and radars give rescue teams access to a higher field of view, saving the need to spend resources on manned helicopters. Where larger aerial vehicles would prove perilous or inefficient, drones, thanks to their small size, are able to provide a close-up view of areas.

PRECISION AGRICULTURE

Farmers and agriculturists are always looking for cheap and effective methods to regularly monitor their crops. The infrared sensors in drones can be tuned to detect crop health, enabling farmers to react and improve crop conditions locally, with inputs of fertilizer or insecticides. It also improves management and effectuates better yield of the crops. 

SEARCH AND RESCUE

Presence of thermal sensors gives drones night vision and makes them a powerful tool for surveillance. Drones are able to discover the location of lost persons and unfortunate victims, especially in harsh conditions or challenging terrains. Besides locating victims, a drone can drop supplies to unreachable locations in war torn or disaster stricken countries. For example, a drone can be utilized to lower a walkie-talkie, GPS locator, medicines, food supplies, clothes, and water to stranded victims before rescue crews can move them to some  place else.

WEATHER FORECAST

Drones are being developed to monitor dangerous and unpredictable weather. Since they are cheap and unmanned, drones can be sent into hurricanes and tornadoes, so that scientists and weather forecasters acquire new insights into their behavior and trajectory. Its specialized sensors can be used to detail weather parameters, collect data, and prevent mishaps.

WILDLIFE MONITORING

Drones have served as a deterrent to poachers. They provide unprecedented protection to animals, like elephants, rhinos, and big cats, a favorite target for poachers. With its thermal cameras and sensors, drones have the ability to operate during the night. This enables them to monitor and research on wildlife without causing any disturbance and provides insight on their patterns, behavior, and habitat.

LAW ENFORCEMENT

Drones are also used for maintaining the law. They help with the surveillance of large crowds and ensure public safety. They assist in monitoring criminal and illegal activities. In fact, fire investigations, smugglers of migrants, and illegal transportation of drugs via coastlines, are monitored by the border patrol with the help of drones.

SUBMITTED BY:

Thushara R B

Yogini E

Pradeep A

Sahana D

REFERENCES:

TELL ME WHY (monthly)

en.wikipedia.org/wiki/Unmanned_aerial_vehicle

https://www.allerin.com

FLY BY PHYSICS

Introduction

For thousands of years, people have wanted to fly. Our legends and fairy tales are full of humans and animals that can fly –effortlessly gliding through that air. In real life, of course, no one can just fly into the air. We don’t have wings to keep and a power to keep the wings moving through the air to sustain the lift necessary or flight.

 “ Planes and birds are both affected by same forces in flight. They have to able to provide enough lift force to oppose the weight force.”

Our attempts to fly have taken us from flimsy paper hot-air balloons and strange-looking gliders to supersonic jet planes. We have learned about the forces of flight, and we know what it takes to keep birds and planes in the air.

Force can be defined as a push or pull. Unbalanced forces produce an acceleration of an object in the direction of the resultant force. Four main forces affect the flight abilities of birds and planes-weight, lift, thrust and drag.

Weight and Lift

We all know the gravity is a force that pulls everything towards the earth’s surface. This pull is called weight force.

Planes and birds have to be able to provide enough lift forces to oppose the weight force. Lift is a force that acts upwards against weight and is caused by the air moving over and under the wings.

Thrust and Drag

The power source of a bird or plane provides the thrust. Thrust is the force that moves the object forward. Thrust is provided by:

·       Muscles –for birds and other flying animals.

·       Engines-for flying machines.

·      Gravity-for glides that actually fly by always diving at a very shallow angle (birds do this too when they glide).

The force working against thrust is called drag. It caused by air resistance and acts in the opposite direction to the motion. The amount of drag depends on the shape of the objects, the density of the air and the speed of the object. Thrust can overcome or counteract the force of drag.

How it works

An object in flight is constantly engaging in a tug of war between the opposing forces of lift, weight, thrust and drag. Flight depends on these forces-whether the lift force is greater than the weight force and whether thrust is greater than drag forces.

Lift and drag are consider aerodynamic forces because they exist due to the movement of an object through the air. The weight pulls down on the plane opposing the lift created by air flowing over the wing. Thrust is generated by the propeller and opposes drag caused by air resistance. During take-off, Thrust must counteract drag and lift must counteract the weight before the plane can become airborne.

If  a plane or bird flies straight at a constant speed

·        Lift force upwards=weight force downwards

·        Thrust force forward=opposing force of drag

A plane can lose altitude by reducing thrust. Drag becomes greater than thrust and the plane slow down. This reduces lift and the plane descends.

A scientific fact

our human bodies can shied up to 1.5 liters of water   flying in the air for an average 3 hours. This is due to dehydration where we are spending a certain amount of time in a reduced oxygen environment.

Historical fact

The wright brothers invented and flow the first airplane in 1963 it is considered the worlds first sustained and controlled heaviest than air power flight. Their air craft the “height flyer” How about 120 feet.

Conclusion

long flights come when these four drag gravity and thrust and lift are balanced some planes are meant to be theorem with a lot of four because on extra thrust to over come gravity long distance files are often built with this same design planes that are built to spend a long time in the air usually have a lot of lift but little thrust thus planes and birds fly a slow and gentle flight.

SUBMITTED BY:

Shayana

Sujith

Lalan T B

Thilaka

1st  M. Sc. {2^nd Semester}     

SUBMITTED ON: 20/04/2019

REFERENCE:

Internet

journal

AURORA

Introduction:

A Natural electrical phenomenon characterized by the appearance of streamers of reddish or greenish light in the sky , especially near the northern or southern magnetic pole . The effect is caused by the  interaction of charged particles from the sun with atoms in the upper atmosphere. In northern and southern regions it is respectively called AURORA BOREALIS or Northern lights and AURORA AUSTRALIS or Southern Lights.

An Aurora( plural : auroras or aurorae ) ,sometimes referred to as polar lights , northern lights, southern lights , is a natural light display in the earth’s sky, predominantly seen in the high – latitude regions.

Auroras are produced when the magnetosphere is sufficiently disturbed by the solar wind that the trajectories of charged particle in both solar wind and magnetospheric plasma, mainly in the form of electrons and protons, precipitate them into the upper atmosphere due to Earth’s magnetic field, where their energy is lost.

An Aurora is the impressive end result of a series of events that starts at the sun. The sun constantly emits a stream of charged particles known as the solar wind into the  depths of the solar system. When these particles reach a planet, such as Earth, they interact with the magnetic field surrounding it ( the magnetosphere ), compressing the field into a teardrop shape and  transferring  energy to it.

Because of the way the lines of a magnetic field can change, the charged particles inside the magnetosphere can then be  accelerated into the upper atmosphere . Here they collide with molecules such as nitrogen and oxygen, giving off energy in the form of light . This creates ribbon of colour that can be seen across the sky close to the planet’s magnetic north and south poles – this is the aurora.

Gas giant auroras:

Using measurements from spacecraft, such as Cassini, or images from telescopes, such as the Hubble Space Telescope, space physicists have been able to verify that some of our closest neighbours have their own auroras. Scientists do this by studying the electromagnetic radiation received from the planets, and certain wavelength emissions are good indicators of the presence of auroras.

Each of the gas giants (Jupiter, Saturn, Uranus and Neptune) has a strong magnetic field, a dense atmosphere and as a result, its own aurora. The exact nature of these auroras is slightly different from Earth’s, since their atmospheres and magnetospheres are different. The colours, for example, depends on the gases in the planet’s atmosphere. But the fundamental idea behind the aurora is the same.

Interaction of solar wind:

The solar wind is a constant outflow of electrons and protons from the Sun, always present and buffeting Earth’s magnetic field. The background solar wind flows at approximately one million miles per hour.

Even though auroras are best seen at night, they are actually caused by the sun. The sun sends us more than heat and light; it sends lots of other energy and small particles our way. The protective magnetic field around Earth shields us from most of the energy and particles, and we don’t even notice them.

But the sun doesn’t send same amount of energy all the time. There is a constant streaming solar wind and there are also solar storms. During one kind of solar storm called a coronal mass ejection, the sun burps out a huge bubble of electrified gas that can travel through space at high speeds.

When a solar storm comes toward us, some of the energy and small particles can travel down the magnetic field lines at the north and south poles into Earth’s atmosphere. There, the particles interact with gases in our atmosphere resulting in beautiful display of light in the sky. Oxygen gives off green and red light. Nitrogen glows blue and purple.

A typical aurora display consists of these forms appearing in the above order throughout the night.

• Red: At the highest altitudes, excited atomic oxygen emits at 630nm; low concentration of atoms and lower sensitivity of eyes at this wavelength makes this colour visible only under more intense solar activity. The low number of oxygen atoms and their gradually diminishing concentration  is responsible for the faint appearance of the top parts of the “curtains”. Scarlet, Crimson and carmine are the most often seen hues of red for the auroras.

• Green :  At lower altitudes, the more frequent collisions suppress the 630 nm mode: rather the 557.7 nm emission dominates. Fairly high concentration of atomic oxygen and higher eye sensitive in green makes auroras the most common.

•Blue: At lower altitudes, atomic oxygen is uncommon, and molecular nitrogen and ionized molecular nitrogen take over in producing visible light emission, radiating at a large no. of wavelengths in both red and blue parts of the spectrum, with 428 nm being dominant.

•Ultraviolet:  Ultraviolet radiation form auroras have been observed with the requisite equipment. Ultraviolet aurora have also been seen on Mars, Jupiter and Saturn.

•Infrared: Infrared radiation, in wavelengths that are within the optical window, is also part of many auroras.

•Yellow and pink are a mix of red and green or blue. Other shades of red, as well as orange, may be seen on  rare  occasions.

How does the altitude effect the colour of the aurora?

The strong , green light originates at altitudes of 120km to 180km. Red northern light occurs at even higher altitudes, while blue and violet occur mostly below 120km. When the sun is “stormy”, red colours occurs at altitudes of 90 to 100km. Entirely red Northern lights may sometimes be seen, particularly at low altitudes.

The different colours of aurora at different altitude relates to the varying composition of the earths atmosphere and its decreasing density moving away from the surface.

Auroras of different planets:

Earth’s Aurora:

The resulting ionization and excitation of atmospheric constituents emits light of varying colour and complexity. The form of aurora, occurring within  bands around both the polar region.

Jupiter Aurora:

Jupiter’s main Auroral ring maintains a constant size. This is due to its formation through interaction within its own magnetic environment. Jupiter’s moon are also believed to be able to influence auroras.

Saturn Aurora:

On Saturn, the strongest auroras are in the UV and infrared bands of the spectrum and so would not visible to the human eye. But weaker pink and purple auroras have also been spotted.

Venus Aurora:

Astronomers love a good mystery, and here’s one they’ve pondered for decades. That is, Venus may have green auroras despite the fact it has no magnetic field of its own.

Mars Aurora:

 On Mars, aurora appear near areas of magnetised rock within the planet’s crust rather than near the poles, when charged solar particles concentrate towards them. This type of aurora formation is totally unique to mars as far as scientists are aware.

Summary:

Witnessing an aurora first hand is a truly awe-inspiring experience. The natural beauty of the northern or southern lights captures the public imagination unlike any other aspect of space weather. But auroras aren’t unique to Earth and can be seen on several other planets in our solar system.

An Aurora is the impressive end result of series of events that starts at the sun. The sun constantly emits a stream of charged particles known as the solar wind into the depths of the solar system. When these particles reach a planet, such as Earth, Jupiter, they interact with the magnetic field surrounding it, compressing the field into a teardrop shape and transferring energy to it.

Because of the way the lines of a magnetic field can change, the charged particles inside the magnetosphere can then be accelerated into the upper atmosphere. Here they collide with molecules such as nitrogen and oxygen, giving off energy in the form of light. This creates a ribbon of colour that can be seen across the sky close to the planet’s magnetic north and south poles- this is the Aurora.

SUBMITTED BY:

Priyalatha .M.

Ramyashri.

Preethi.

Sahana Rao L.N.

1st M.Sc. (2^ndSemester)     

SUBMITTED ON: 10^th April 2019

REFERENCE:

Internet

Journal